package com.vmix.vmixmobiledemo;


import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Stack;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;

import com.vmix.vmixmobiledemo.SoftCache;

public class ImageLoader {
	
	private SoftCache cache = new SoftCache();
  
	final int stub_id = R.drawable.icon;
	
	public ImageLoader(Context context){
		//Make the background thread low priority. This way it will not affect the UI performance
		photoLoaderThread.setPriority(Thread.NORM_PRIORITY-1);

	}
	

    public void DisplayImage(String url, Activity activity, ImageView imageView)
    {
    	if(cache.get(url) != null)
    		imageView.setImageBitmap(cache.get(url));
        else
        {
            queuePhoto(url, activity, imageView);
            imageView.setImageResource(stub_id);
        }    
    }
        
    private void queuePhoto(String url, Activity activity, ImageView imageView)
    {
    	//This ImageView may be used for other images before. So there may be some old tasks in the queue. We need to discard them. 
        photosQueue.Clean(imageView);
        PhotoToLoad p=new PhotoToLoad(url, imageView);
        synchronized(photosQueue.photosToLoad){
        	photosQueue.photosToLoad.push(p);
        	photosQueue.photosToLoad.notifyAll();
        }
        
        //start thread if it's not started yet
        if(photoLoaderThread.getState()==Thread.State.NEW)
            photoLoaderThread.start();
    }
    
    private Bitmap getBitmap(String url) 
    {

        //from web
        try {
            Bitmap bitmap=null;
            URL thumbnailURL = new URL(url);
            HttpURLConnection conn= (HttpURLConnection)thumbnailURL.openConnection();
            conn.setDoInput(true);
            conn.connect();
            InputStream is = conn.getInputStream();
            
            bitmap = BitmapFactory.decodeStream(is);
            return bitmap;
            
        } catch (Exception ex){
           ex.printStackTrace();
           return null;
        }
    }

    //Task for the queue
    private class PhotoToLoad
    {
        public String url;
        public ImageView imageView;
        public PhotoToLoad(String u, ImageView i){
        	url=u; 
        	imageView=i;
        }
    }
    
    PhotosQueue photosQueue=new PhotosQueue();
    
    public void stopThread()
    {
    	photoLoaderThread.interrupt();
    }
    
    //stores list of photos to download
    class PhotosQueue
    {
        private Stack<PhotoToLoad> photosToLoad = new Stack<PhotoToLoad>();
        
        //removes all instances of this ImageView
        public void Clean(ImageView image)
        {
            for(int j=0 ;j<photosToLoad.size();){
                if(photosToLoad.get(j).imageView==image)
                    photosToLoad.remove(j);
                else
                	++j;
            }
        }
    }
    
    class PhotosLoader extends Thread {
        public void run() {
        	try {
	        	while(true)
	        	{
	        		//thread waits until there are any images to load in the queue
		        	if(photosQueue.photosToLoad.size()==0)
		        		synchronized(photosQueue.photosToLoad){
		        			photosQueue.photosToLoad.wait();
		        		}
		            if(photosQueue.photosToLoad.size()!=0)
		            {
		                PhotoToLoad photoToLoad;
		                synchronized(photosQueue.photosToLoad){
		                	photoToLoad=photosQueue.photosToLoad.pop();
		                }
		                Bitmap bmp=getBitmap(photoToLoad.url);
		                cache.put(photoToLoad.url, bmp);
		                if(((String)photoToLoad.imageView.getTag()).equals(photoToLoad.url)){
		                    BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad.imageView);
		                    Activity a=(Activity)photoToLoad.imageView.getContext();
		                    a.runOnUiThread(bd);
		                }
		            }
		            if(Thread.interrupted())
		            	break;
	        	}
        	} catch (InterruptedException e) {
        		//allow thread to exit
			}
        }
    }
    
    PhotosLoader photoLoaderThread=new PhotosLoader();
    
    //Used to display bitmap in the UI thread
    class BitmapDisplayer implements Runnable
    {
        Bitmap bitmap;
        ImageView imageView;
        public BitmapDisplayer(Bitmap b, ImageView i){bitmap=b;imageView=i;}
        public void run()
        {
            if(bitmap!=null)
                imageView.setImageBitmap(bitmap);
            else
                imageView.setImageResource(stub_id);
        }
    }


	
}




